i know me math, 1+1=2 and so forth, but i was wondering what is better for reception, a single huge (8ft) whip or 2 shorter (4ft firestiks). i was lookin at this thread CB mods.... and there was mention of both, but never a definate better of the 2. jw cause i like the dual look, but if i cant hear anything more than a quarter mile away, it wouldnt exactly be worth it now would it? daddy griggs i was hoping you could help out on this one you shortwave gawd. hell, anyone's input would be nice before i start getting drill happy.

 

The higher the better from what I understand....

 

The dual whips are called "Co-Phased" antennas. They increase your gain front-to-back which is why truckers use them. They don't care about talking to people in towns. They want more power to the front and back which usually goes right along the highway they are on.

However, in order for co-phased antenna to work properly, you need a certain horizonatal distance between antennas. I [i]think[/] it is 1/4 wavelength which is 8ft. This is easy on an 18-Wheeler. It is impossible on our trucks. We aren't wide enough for the co-phased system to work properly.

In my opinion, the best CB antenna will be a permanent mount dead-center in the roof. Make sure it is a high quality antenna, not some radio shack piece of junk. An 8' whip on the bumper will work, but it's going to have a funky radiation pattern since there is no ground plane to one side.

 

And co-phase only works well (as Matt just said) when you can get the antenna's a multiple of 1/4 wave apart -- that's 8 feet approx. for CB -- not easy to get on our trucks so co-phase will be marginal and have a funny shaped pattern.

Should be a 3db or more difference between a long whip and short antenna. That corresponds to about a 2:1 difference in signal, with the shorter whip being the lesser obviously.

Most short antenna's on a truck are more than 3db down from a full 1/4 wave whip.

Although it's nice to center it on the truck, our trucks don't extend far enough to be a good "ground radial" for CB frequencies anyway. As long as it's firmly grounded to the truck at it's base, you should be okay. Mine HF ham antenna's and my CB whip are on the rear fenders. Roof mounting a CB antenna sucks for offroading and don't even think about a magmount if you do wooded trails. Nothing beats a permanent mount. Period.

Also, I've been using 4 foot K40-Flex antennas but I've now broken TWO of them. I'm not getting them anymore. I thought the extra flex would make them more durable, but the Pine Barrens apparently disagree with that assessment.

 

i used to have a wilson lil wil magna mount and then upgraded to an 8' whip and was very pleased with the results. the magna mount was on the roof and the whip is on my toolbox. if i was to ground the antenna would i get better, clearer, anything of that sort reception/transmission?

 

You don't ground the antenna itself, but the cable sheild that feeds it, right at the base of the antenna. Most 3/8-24 mounts for whips are designed to ground the proper part. If you have an aluminum toolbox, make sure it is grounded to the body. Sometimes that happens when you mount it, other times you need to specifically do something to ground it.

How's it tune? SWR okay and all? Chances are, it's alright if you can tune it fine.

On small whips, the reactance of the wound portion can make tuning funny. You can sometimes tune them over a bad ground, but the performance will be bad. Just because an antenna is tuned, doesn't mean it radiates or receives well.

I can take a 50 ohm resistor and put it on the end of an antenna cable, and it will give you a a 1:1 SWR -- but it won't work worth diddly!

 

so john, whats the next whip you are going to get if the other too have been a little too flexible for your use? i'm still trying to figure out a mounting spot for the whip, since i have the toolbox, and want full function of it. any way i can form a bracket that attaches to the tool box that i can mount the whip to?

 

I guess you don't want to drill your truck, eh?

This is what I do, both sides.





Edit: And of course, these could be put on your toolbox as well. These are rather expensive stainless steel type, but plated cast metal ones are available cheap at Radio Shack. I put one of those on Sawred's (Mike's) truck for him not that long ago.

As far as which whip, I'm leaning towards the regular K-40 or the Firestick. Something about 4 feet long (not too tall) and hopefully more durable. I had a spring under the K-40 flex but it was hard to tune that way. Maybe the full diameter antenna will be a bit more "broadband" and I can get it tuned with a spring under it. I hoped the "flex" model wouldn't need a spring -- but it's just too flimsy for offroading -- sadly since I've now spent $14 TWICE to find that out, lol.

 

ive got a mount that i bought from radio shack. theyve got so many to choose from, at least the one close to here. i wasnt too fond of drilling into my truck so thats why i didnt get a whip until i got my toolbox. you can see my whip mounted(just under the lip of the lid) but not how its mounted on my cardomain site. and ive got a low profile toolbox. if yours isnt low profile you can side mount the whip.

 

While we're on the subject, what do ya'll think about mounting a 3-4' firestick fiberglass jobbie to the center of the front of the bed, right behind the cab? Would that create some funky reception issues? I'd like to keep the soft tonneau but maybe cut a small hole in the middle of the leading edge. I can't really say why, but I'm thinking of upgrading to a permanantly installed CB unit..

 

It will be funny, just because of the proximity of the cab roof. Primarily for transmit as far as the effect being really noticeable, I should think. Also, you'll be giving yourself a good dose of RF, lol!

But it might be fine for what you need it for.

 

^^^^^ Effects of constant RF exposure ^^^^^

:)

 

[John replies, eyes drifting in an out of focus while drool seeps from the corner of his mouth]

Whaddya' mean, Matt?...

 

I love my firestik and have heard they get better reception than those big whips. It's worked great for what I need...I still can't fit in our parking garage tho which reminds me...

Daddy Griggs, I have a mission for you, should you choose to accept it.
I have an idea for my antenna. It's mounted on the back of my toolbox on an L bracket dealio. I'd like a way to raise it and lower it at the flip of a switch. Is it possible with a firm grasp of nothing electrical? I'm thinking a...what's it called...like an actuator? Geez I can't think..it looks like a mini shock and it can push up or allow the arm to lower...
I park in a parking garage at work and like being in the shade, especially in our brutal summers but I drive 36 miles to and from work so I'd really like quick CB access. I could just screw in my firestik but I'd rather not go crawlin all over in my shirt and tie. Any thoughts?
Also...*coughfoglightmodformytruckcough*

Thanx! You are the man

 

Where do you have it mounted. I hadn't done the math, but didn't realize a 4' stick would be that much of a problem. That actually changes things. I love my garage..

 

No 4 foot helically wound whip is going to outdo a full size 1/4 wave (properly installed) on reception. Banish that idea and anyone who tells you so.

A SPECIFIC 4 foot antenna compared to a SPECIFIC 1/4 wave whip (that was not properly installed) -- yes, I can believe that.

There's surely some way to do that, Bryan. But it would require a "Griggs Rig" to do it. I would think you'd want a "gear motor" type gadget contrained by limit switches to 90 degree rotation. Mount the whip offset from the center of the rear of the tool box and you could have it lay down behind the toolbox at the flip of switch, or back up again -- Viagra for your antenna!

But I know of nothing in particular. You need outdoor capability and 12 volt operation. You could look here at some surplus gear motors (24 volt motors work fine for something like this when run on 12 volts): http://www.allelectronics.com

They have a section on motors and gear motors and I have occasionally seen surplus items that are EXACTLY what you want.

I'm watching for something that I could use to make a motorized mount for my driving lamps so I can change the angle from in the cab. That would be great for offroading. Not sure exactly how I'm doing it yet, though. I'm waiting for "inspiration to strike" when I see something that looks possible to use.

 

my 4 foot firestik is mounted on a spring in the forward stake hole on the passanger side
tunes fine, great reception, no holes drilled - survived the pines
you can get the whole set up on line for about $30

 

It's mounted on the back of my toolbox. On the L bracket is a CB spring mount then the antenna. The buldge of the spring is parallell with the toolbox top...does that makes sense?

 

Wow....I'd love to have a Griggs Original on my truck :)

Thanx for the info John. Sounds like more than I can get into on my own but yes I'm looking for viagra for my antenna :)

 

man i was runnin around with my hellas on and my highs and i lost a bit of my ground view cuz the fogs shut off with the highs. how is this here fog mod done and how risky is it? thanks guys

how do you properly install a whip? ive got mine done as follows: L-bracket(wider one with four bolt holes) drilled/installed onto aluminum diamond plate toolbox as high as it will go, aluminum(i believe) spring then 8' whip, coax cable running from bottom of bracket under toolbox over back of bed through seam in door and to the back of my un-mounted cb radio. no grounds on the antenna or toolbox as the toolbox is not bolted to the truck, it is clamped and where the clamp touches the truck is rubber and the toolbox touches paint.

i also have an amp and sub and the power wire to the amp is tucked under the door sill along with the coax cable. any interference here? thanks guys.

 

That's how mine is mounted and it works fine. I have a spring to keep it from getting damaged when wheeling and a tennis ball to keep the thing from beating up the cab. The tennis ball is important tho if you're going to use a spring tho....